The purpose of this core unit is to act as the organizational and administrative center of the Program, and to provide specialized services that are ubiquitous to all projects and cores within this proposal. Common needs, including program administration, secretarial support, word processing, budgeting and ordering of research and administrative supplies, as well as equipment, are integrated in the core to avoid unnecessary duplication. In addition, Core A is responsible for on-line searches of the biomedical literature and for final preparation of manuscripts and correspondence. Finally, the core is in charge of regularly scheduling meetings of participating investigators with consultants and advisory committees, as well as for organizing seminars related to the overall goals of the PPG.